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opencc-zeroDec 2013View details →

Data from: Variation in early life testosterone in a wild population of red deer

1. Individual differences in circulating hormone concentrations can affect life history traits throughout an animal's life. Despite this, relatively little is known about the potential drivers or consequences of individual variation in hormone levels, particularly in early life. In animals showing maternal care, early development is often dependent on maternal characteristics and condition. It is therefore possible that individual hormone profiles early in life are dependent on condition-linked characteristics of the mother. 2. Using data from a long-term study of a wild red deer (Cervus elaphus) population, we investigated the potential role of maternal effects on offspring early life testosterone concentrations and the relationship between these testosterone levels and juvenile survival. 3. Most of the variation among neonatal calves was accounted for by their age and sex. Both sexes showed a steep decline in testosterone levels within 24 hours of birth, although concentrations were consistently higher in males, and females showed a steeper decline in testosterone after 24 hours. Furthermore, male calves born in years after a brother had lower concentrations than those who were preceded by a sister or who were firstborns. We did not find any evidence of repeatable differences among mothers in the testosterone levels of their calves, but there was significant inter-annual variation across the 17-year study period. 4. We also found early life testosterone to be associated with calf survival, but only amongst individuals already at higher mortality risk: male calves born to first-time mothers were increasingly less likely to survive with higher neonatal testosterone concentrations. 5. These results support the suggestion that a neonate's circulating testosterone concentrations can be linked to both individual and maternal characteristics, and that inter-individual variation in these levels can have implications for juvenile fitness within a wild mammal population.

opencc-zeroDec 2015View details →

Data from: Testosterone production ability predicts breeding success and tracks breeding stage in male finches

Testosterone (T) is an important mediator of reproductive behaviours and potential target for selection. However, there are few data relating natural variation in T to fitness estimates. Here, we used the GnRH challenge (an injection of gonadotropin-releasing hormone which stimulates maximal T release), to examine how individual differences in T relate to reproductive success and how T changes across date and breeding stage. We measured pre- and post-challenge T, in captive male Gouldian finches (Erythrura gouldiae), before and after introducing females, and across breeding stage. Post-challenge T before introducing females positively predicted breeding success. Post-challenge T levels were unrelated to date, but strongly related to stage; T production ability was strongly attenuated in incubating males. Prechallenge T levels related only to date. Our results suggest that T production ability is an important target for selection and that when males invest heavily in parental care they reduce their sensitivity to GnRH.

opencc-zeroNov 2021View details →

Testosterone amplifies the negative valence of an agonistic gestural display by exploiting receiver perceptual bias

Many animals communicate by performing elaborate displays that are incredibly extravagant and wildly bizarre. So, how do these displays evolve? One idea is that innate sensory biases arbitrarily favor the emergence of certain display traits over others, leading to the design of an unusual display. Here, we study how physiological factors associated with signal production influence this process, a topic that has received almost no attention. We focus on a tropical frog, whose males compete for access to females by performing an elaborate waving display. Our results show that sex hormones like testosterone regulate specific display gestures that exploit a highly conserved perceptual system, evolved originally to detect "dangerous" stimuli in the environment. Accordingly, testosterone makes certain gestures likely appear more perilous to rivals during combat. This suggests that hormone action can interact with effects of sensory bias to create an evolutionary optimum that guides how display exaggeration unfolds.

opencc-zeroFeb 2022View details →

Patterns of Testosterone in Male White-tailed Deer (Odocoileus virginianus): Seasonal and Lifetime Variation

Testosterone is strongly associated with the annual development of antlers in cervids, but. endocrine research on wild, freely breeding ungulates is often done without repeated capture of known-aged individuals. As a result, our knowledge on how testosterone fluctuates over the course of a lifetime and variation in lifetime patterns among individuals is limited. We investigated patterns of testosterone in a freely breeding population of white-tailed deer (Odocoileus virginianus) in Alabama, USA that breeds in January. Testosterone peaked during the height of the breeding season, despite this period occurring approximately two months later than in most temperate-region, white-tailed deer populations. Age-related differences in testosterone were only prevalent during the breeding season, with bucks ≥3.5 years old having greater testosterone (853 ng/dl ±96 SE; P = 0.012) than bucks 1.5–2.5 years old (364 ng/dl ±100 SE). Additionally, an individual's testosterone level as a yearling was not positively associated with their lifetime maximum testosterone level (P = 0.583), and an individual's mean testosterone level was positively associated with lifetime testosterone variation (P < 0.001). To our knowledge our study is one of the first to assess how testosterone early in life might relate to individual testosterone later in life. We believe these data provide insight into lifetime hormonal patterns in cervids, and that these patterns may indicate intraspecific variation of lifetime reproductive strategies.

opencc-zeroSep 2022View details →

Supplementary data for: Maternal testosterone and offspring birth weight: A Mendelian randomization study

Evidence showed maternal androgen levels in both healthy/general population and populations with hyperandrogenic disorders were inversely associated with offspring's birth weight. We aimed to investigate the causal effect of maternal testosterone levels in general population on offspring's birth weight and preterm delivery risk using two-sample Mendelian randomization (MR) method. We obtained independent genetic instruments from a sex-specific genome wide association study with up to 230,454 females of European descent from UK biobank. Genetic instruments with consistent testosterone effects but no aggregate effect on sex-hormone binding globulin were used to perform the main analysis. Summary-level data of offspring's birth weight with offspring's genotype adjusted was obtained from a study with 210,406 females of European descent. Summary-level data of preterm delivery was obtained from the FinnGen study (6,736 cases and 116,219 controls). For outcome of offspring's birth weight, the numbers of instruments included in final MR analyses were 123, 128 and 91 respectively. For outcome of preterm delivery, the numbers were 115, 120 and 83 respectively. The present data files show the genetic instruments and their effects on exposures and outcomes. Pleiotropic genetic instruments that excluded in the MR analysis were also provided in the files.

opencc-by-4.0Jun 2024View details →

Brodinlab/Gender-affirming-Testosterone-treatment: Gender-affirming-Testosterone-treatment.v1

Data and code to reproduce figures of Lakshmikanth et al, 2024.

FIG. 4. Average T in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 4. Average T concentration for calling and non-calling males of L. grylio across months, where like letters indicate non-significant differences in concentrations and numbers indicate sample size. A significant seasonal decrease was observed in circulating T (F3,31 ¼ 16.187; P, 0.001).

FIG. 5. A in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 5. A linear regression of ambient call rates averaged over one minute and circulating T for individual males. Individual circulating T was positively correlated with the number of conspecific calls recorded during each respective evening of sampling (R2 ¼ 0.285; Ŷ ¼ i 3895.38þ31.08Xi; P, 0.01).

FIG. 7 in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 7. Linear regression of circulating CORT and glucose concentrations in calling and non-calling males shows the amount of glucose in circulation positively correlates with circulating CORT within non-calling males (R2 ¼ 0.665; Ŷ ¼ 31.447 þ 0.098X; P, 0.001). The regression i i line is only indicative of a relationship between CORT and glucose concentrations for non-calling males, as there was no significant relationship between CORT and glucose in calling males (R2 ¼ 0.149; P ¼ 0.305).

FIG. 2 in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 2. (A) A linear regression of SVL and body mass suggests a positive linear allometric relationship between the variables (R2 ¼ 0.21; Ŷ ¼ i 37.64þ1.26Xi; P ¼ 0.02). (B) A boxplot of the residuals from Figure 2A for the ethotypes indicates calling males have significantly higher body masses than what is predicted by the SVL and body mass regression line (t23 ¼ 5.599; P, 0.001). Box size is based on the range of data points falling between the 2nd and 3rd quartiles. Mean is represented by the filled circle and median by the bold line.

FIG. 1 in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 1. Boxplots illustrating average (A) body mass, (B) snout–vent length (SVL), and (C) body condition index (BCI ¼ mass/SVL) for calling (n ¼ 11) and non-calling (n ¼ 14) males. Calling males had significantly higher body masses (A; t23 ¼ 3.725; P ¼.001) and body condition indices (C; t23 ¼ 5.599; P, 0.001) than non-callers. SVL did not significantly differ (n.s.) between the two ethotypes (B; t23 ¼ 0.577; P ¼ 0.570). Box size is based on the range of data points falling between the 2nd and 3rd quartiles. Mean is represented by the filled circle and median by the bold line. Open circles denote potential outliers that were not omitted from statistical analysis.

FIG. 3 in Testosterone and Corticosterone Profiles and Body Condition of Calling and Non-calling Lithobates grylio

FIG. 3. (A) Average circulating T in calling (n ¼ 20) and non-calling males (n ¼ 16). The numbers on the bars indicate sample size. T was significantly higher in callers (t34 ¼ 2.987; P, 0.01). (B) Average circulating CORT in calling (n ¼ 19) and non-calling (n ¼ 17) males, where CORT was elevated in non-callers (t ¼ 2.153; P ¼ 0.0381). Box size is based on the range of data points falling between the 2nd and 3rd quartiles. Mean is represented by 36 the filled circle and median by the bold line. Open circles denote potential outliers that were not omitted from statistical analysis.

opennotspecifiedMar 2023View details →

FIG. 3 in Plasma Vitellogenin and Testosterone in Diamond-backed Terrapins (Malaclemys terrapin) during the Nesting Season in Coastal New Jersey

FIG. 3. Plasma testosterone (A) and vitellogenin (B) concentrations in relation to midline plastron length in Diamond-backed Terrapins captured during early (June; green triangles), middle (early July; blue squares), and late (late July–early August; red circles) nesting season at the Cape May Peninsula, New Jersey and the Hackensack Meadowlands, New Jersey.

opennotspecifiedMar 2023View details →

FIG. 1 in Plasma Vitellogenin and Testosterone in Diamond-backed Terrapins (Malaclemys terrapin) during the Nesting Season in Coastal New Jersey

FIG. 1. Mean plastron length (6 SEM) of Diamond-backed Terrapins captured during early (June), middle (early July), and late (late July– early August) nesting season. Dashed lines within each box indicate mean of data, while solid lines inside the boxes indicate the median. Varying letters indicate significant differences (P, 0.05) between sampling periods. Mean and median overlap in some categories, and both lines may not be visible.

opennotspecifiedMar 2023View details →

FIG. 2 in Plasma Vitellogenin and Testosterone in Diamond-backed Terrapins (Malaclemys terrapin) during the Nesting Season in Coastal New Jersey

FIG. 2. Mean circulating plasma (A) testosterone concentration (6 SEM) and (B) vitellogenin concentration (6 SEM) of Diamond-backed Terrapins captured during early (June), middle (early July), and late (late July–early August) nesting season. Dashed lines within each box indicate mean of data, while solid lines inside the boxes indicate the median. Varying letters indicate significant differences (P, 0.05) between sampling periods. Mean and median overlap in some categories, and both lines may not be visible.

opencc-zeroApr 2020View details →

Concordance table for oral testosterone undecanoate

Concordance analysis was performed to identify the best post-dose T assay time-point to guide any necessary dose-adjustment in oral TU patients. Concordance is defined herein to describe the extent of agreement between a decision to adjust the oral TU dose (up or down) when a single circulating T concentration in remains in the hypogonadal range [i.e., <252 ng/dl (9 nmol/L) for this study] or supraphysiological range [i.e., >907 ng/dL (31 nmol/L)] and the desired outcome of that decision (i.e., a circulating T level in the eugonadal range) is achieved.

closedIPD-NOFeb 2026View details →

The Effects of Semaglutide vs Testosterone Replacement Therapy on Functional Hypogonadism and Sperm Quality in Men With Type 2 Diabetes Mellitus and Obesity

ClinicalTrials.gov study NCT06489457. IPD Sharing: NO. Countries: 1. Publications: 1.

closedIPD-NOFeb 2026View details →

A Dose Ranging Study to Examine TDS-Testosterone 5%

ClinicalTrials.gov study NCT01894308. IPD Sharing: NO. Countries: 1. Publications: 1.

restrictedIPD-UNDECIDEDFeb 2026View details →

Testosterone and Weight Loss

ClinicalTrials.gov study NCT01616732. IPD Sharing: Not stated. Countries: 1. Publications: 2.