The goal of the present studies was to compare direct effects of porcine FSH (pFSH) on [125I]pFSH-binding sites with effects of pFSH on FSH receptor mRNA in cultured porcine granulosa cells. Cells from immature follicles were cultured on laminin-coated plates in serum-free medium for up to 6 days in the absence or presence of pFSH (1-100 ng/ml) or cholera toxin (0.04-400 ng/ml), which activates adenylyl cyclase independently of the FSH receptor. RRA indicated that [125I] pFSH binding to cells cultured without stimulator increased more than 10-fold with time in culture. Addition of pFSH to cultures resulted in a dose-dependent decrease in binding, assessed after removal of bound pFSH. Equilibrium saturation binding analysis indicated that pFSH (10 ng/ml) caused a 39% decrease in binding sites in cells cultured for 6 days. At the same time, pFSH increased progesterone production 9.5-fold. Cholera toxin (4 ng/ml) increased [125I]pFSH binding 110% and progesterone production 8.9-fold. Northern hybridization analysis of cultured granulosa cell mRNA using a porcine FSH receptor cDNA revealed three transcripts for the FSH receptor [2.2, 3.5, and 4.2 kilobases (kb)], with the major transcript being 4.2 kb in length. Addition of either pFSH (10 ng/ml) or cholera toxin (10 ng/ml) to cultures of granulosa cells increased the intensity of pFSH receptor transcripts compared with control values, with the 4.2-kb message remaining predominant. Hybridization with a porcine LH receptor cDNA revealed different transcripts (2.4, 4.0, 4.7, 7.0, and 11.0 kb), with the major transcript being 4.7 kb in length. Addition of either pFSH or cholera toxin to the cultures increased the intensity of all LH receptor transcripts; however, cholera toxin was more effective than pFSH. pFSH and cholera toxin increased the intensity of each species to different extents, although the 4.7-kb transcript remained predominant. These results indicate that exposure to FSH in culture results in down-regulation of the FSH receptor. Down-regulation is accompanied by increased FSH receptor mRNA levels, suggesting that FSH enhances FSH receptor synthesis.

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\s=b\ Changes in adenosine triphosphatase activity and cellular integrity of rat innerear tissues were observed after removal of adrenal steroids via bilateral adrenalectomy. Statistical significance of total and magnesium ion-dependent adenosine triphosphatase activities of the stria vascularis, spiral ligament, and ampullar dark cells from adrenalectomized animals was detected when compared with those of controls as demonstrated by fluorometric microassay. Although there was a similar reduction of activity in utricular dark-cell tissues, no significant difference between the treated and control animals was observed. An increase of intercellular space and a decrease in basolateral infoldings of cells of the stria vascularis and dark cell regions of adrenalectomized animals were observed. Such data collectively provide indirect evidence that adrenal steroids are involved in the cellular regulation of inner-ear tissues that are concerned with fluid and ionic microhomeostasis.(Arch Otolaryngol Head Neck Surg. 1989;115:817-821) Adenosine triphosphatase (ATPase) has been demonstrated to be a vital enzyme in active transport mech¬ anisms of cells involved in ionic and fluid homeostasis throughout the body. Despite localization and quantitation of inner-ear ATPase by numerous investigators,18 regulation of such in¬ ner-ear activity remains an enigma. Recently, significant change in the sodium -potassium -ATPase (Na --ATPase) activity of selected inner-ear tissues was reported after bilateral adrenalectomy.9 Such data suggested that inner-ear microhomeostasis may be partially influenced by the effect of adrenal steroids on inner-ear ATPase activity.To define further inner-ear ATPase regulation by adrenal steroids, total and magnesium ion (Mg++)-dependent ATPase activities and cellular mor¬ phology of selected inner-ear tissues were determined. The hypothesis tested was that changes in serum levels of adrenal steroids can affect ATPases (eg, calcium and magnesium ions) other than Na-K-ATPase and can affect cellular features of certain inner-ear tissues, leading to fluid and ionic imbalance that may be associated with patients with inner-ear dysfunc¬ tion.The rationale of this investigation was based on the fact that the adrenal gland secretes mineralocorticoids (eg, aldosterone) and glucocorticoids (eg, Cortisol in humans and corticosterone in rats) (Fig 1). Mineralocorticoids af¬ fect ion-transporting epithelial cells by activating the transport of Na+ from the apical side to the vascular side and transport of K+ from the vas¬ cular side to the apical epithelial side. Glucocorticoids increase blood glucose concentration as well as affecting both plasma and fat metabolism. Both min¬ eralocorticoids and glucocorticoids are known to bind to receptor proteins and increase Na-K-ATPase activity.The approach used in this study was to remove endogenous steroids by bi¬ lateral adrenalectomy, thereby creat¬ ing a condition in which inner-ear en¬ zymatic activity and morphological changes could be examined in the ab¬ sence ...

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Structural changes in the cellular morphology of the rat stria vascularis from a standardized region of the basal region and from a standardized region in the apical region of the rat cochlear duct were measured using stereological methods after removal of endogenous levels of adrenal steroids by bilateral adrenalectomy. Although there were some inconsistent and insignificant alterations in the volume density of intermediate and basal cells, a decreased volume density of marginal cells in both the basal region and in the apical region in adrenalectomized (ADX) animals as compared to sham animals was consistent with a concomitant significant increased (p less than or equal to 0.05) volume density of intercellular space as observed in both the basal and apical regions of the stria vascularis of ADX animals. Findings of this study indicate that the strial cells of the stria vascularis react differently and independently in response to the removal of adrenal steroids, and such strial responses occur uniform in both the base and apex.