CARSIA, RV; COX, RM; MCILROY, PJ; JOHN-ALDER, HB; UMDNJ-School of Osteopathic Medicine; Rutgers Univ., New Brunswick; Rutgers Univ., Camden; Rutgers Univ., New Brunswick: Ovarian Influence on Adrenocortical Cell Function in Sceloporus virgatus (Striped Plateau Lizard)
Adrenal steroidogenic (adrenocortical) cells from male Sceloporus undulatus undergo changes in steroidogenic function and sensitivity to ACTH in response to orchiectomy and testosterone maintenance (John-Alder and Carsia, 2004). Here we report the influence of ovariectomy on adrenocortical cell function from S. virgatus. Pre-maturational females were captured and surgically ovariectomized (OVX) or sham-operated (CON) at 7.5-8 months of age. Dispersed adrenocortical cells were prepared and evaluated for progesterone (P4), corticosterone (B), and aldosterone (ALDO) production in response to ACTH 6 months after treatment. With the exception of a 40% reduction in basal P4 by OVX cells, basal and maximal rates of steroidogenesis did not differ between treatments. Steroidogenic responses to ACTH were polyphasic (P < 0.05), having 2-4 response components. A simplified biphasic fit showed high ACTH-sensitive (~300 fM�30 pM) and low ACTH-sensitive (~80 pM�3 nM) components comprising the maximal responses. Compared to CON cells, OVX cells tended to show reduced sensitivity to ACTH for both components, dramatically so for ALDO (by 1/30 to 1/80). In addition, ovariectomy tended to shift the proportional contribution of each ACTH-sensitive component in the maximal response of the steroids. Collectively, the present work with ovariectomized S. virgatus and previous work with orchiectomized S. undulatus show a dynamic but complex role of the gonad in the modulation of lizard adrenal steroidogneic function at the cellular level. Supported by NSF IBN-0135167 (HJ-A).
