Effect of androgens on the cranial suspensory ligament and ovarian position

Androgens have been postulated to have a major role in testicular descent v ia regression of the cranial suspensory ligament, which in normal rodents a nchors the ovary to the retroperitoneum near the lower pole of the kidney. This study aimed to quantitate the degree of descent of the foetal ovary in androgen-treated female mice to determine the role of androgens in regress ion of the cranial suspensory ligament and descent of the testis. Time-preg nant mice were injected with testosterone propionate or methyl testosterone (2.5-3.0 mg) in vehicle on day 13 or 14. Control animals received vehicle only. Newborn mice were anaesthetised and dissected for macroscopic anatomy of the ovary, which was quantified by measuring the vertical distance fi o m the lower pole of the kidney to the lower pole of the ovary. Histological analysis was also performed. The external genitalia were masculinised in a ll females exposed to prenatal androgens. The ovaries of treated animals we re mobile, with no cranial suspensory Ligament, and located slightly caudal to the kidney. Wolffian duct structures were identifiable, but the guberna culum was qualitatively unchanged compared with control females. The ovary was displaced caudally (P < 0.001), but only 15-25% of the distance to the lower abdomen. Exogenous androgens induce regression of the cranial suspens ory ligament, causing the ovary to be more mobile and lower in the abdomina l cavity. However, since the testicular position at birth is at or below th e bladder neck, androgen-mediated regression of the cranial suspensory liga ment is only an adjunct to the control of transabdominal testicular descent . Anat Rec 55:306-315, 1999. (C) 1999 Wiley-Liss, Inc.