Age- and Sex-Dependent Dynamics in Pituitary Thyrotroph and Thyroid Hormones in Dromedary Camels (Camelus dromedarius): A Histochemical Approach.

BACKGROUND

The hypothalamic-pituitary-thyroid axis plays a crucial role in regulating metabolism and reproduction, yet its age- and sex-related dynamics in dromedary camels remain poorly understood.

OBJECTIVE

This study aimed to investigate age- and sex-dependent variations in pituitary thyrotroph morphometry and thyroid hormone profiles in dromedary camels.

METHODS

A total of 90 clinically healthy Brela breed camels of both sexes (aged 2 to ≥11 years) were grouped based on age and physiological status (lactating and non-lactating). Pituitary tissues (n = 60) were subjected to immunohistochemical analysis for thyroid stimulating hormone (TSH)-producing thyrotrophs. Morphometric parameters, including cell count, size, and nuclear dimensions, were measured. Plasma concentrations of TSH, triiodothyronine (T3), and thyroxine (T4) were determined using ELISA.

RESULTS

Thyrotroph cell counts did not differ significantly among groups. However, older camels (≥11 years) showed significantly increased cell and nuclear dimensions (p < 0.05). Plasma TSH levels decreased with age, with peak levels observed in females aged 5-10 years. T3 concentrations varied significantly with age and sex, with higher levels in younger males. T4 levels declined with age but were not significantly influenced by sex (p > 0.05).

CONCLUSION

Thyrotroph morphology and thyroid hormone dynamics in dromedary camels are significantly influenced by age and sex, indicating adaptive modulation of the hypothalamic-pituitary-thyroid axis in response to metabolic and reproductive demands.