The essential findings of the study are that remifentanil's pharmacokinetics are not appreciably different in obese versus lean subjects and that remifentanil pharmacokinetic parameters are therefore more closely related to LBM than to TBW. Clinically this means that remifentanil dosing regimens should be based on ideal body weight (or LBM) and not TBW.
Conditioned medium from cultures of testicular macrophages was capable of stimulating testosterone production in a dose-dependent manner when added to Leydig cells in vitro. Significant stimulation of testosterone production by Leydig cells was observed after 4 h of exposure to testicular macrophage-conditioned medium (TMCM) and thereafter increased progressively for up to 24 h. Treatment of Leydig cells with TMCM together with a maximal dose of LH resulted in greater production of testosterone by Leydig cells than with either agent when used separately. Conditioned medium from macrophages treated with FSH was twice as potent as TMCM from untreated cells. This dose of FSH had no direct effect on Leydig cells. Conditioned medium from cultures of peritoneal macrophages had less effect on testosterone production by Leydig cells than testicular macrophage-conditioned medium. It is proposed that secretory products from testicular macrophages play an important role in testicular function.
Macrophages were isolated from rat testes with trypsin treatment and established in culture using a differential attachment technique. The cells were maintained in culture in Medium 199 at 32 degrees C. The cells were then characterized for their ability to express traditional immunological function as well as to secrete lactate under the regulation of various hormones. The results indicate that viable cultures of macrophages were obtained since: 1) the cells stained intensely for nonspecific esterase, 2) they possessed Fc receptors on their cytoplasmic membranes, 3) they were capable of phagocytosing 3H-labeled E. coli and carbon particles, and 4) they were highly resistant to the effects of trypsin to induce detachment from the culture substrate. These cultures were not contaminated with Leydig cells or Sertoli cells since they were negative for 3 beta-hydroxysteroid dehydrogenase and did not secrete androgen-binding protein (ABP). Most importantly, these cells were capable of responding to follicle-stimulating hormone (FSH) in a dose-dependent manner by increasing the secretion of lactate. Maximal stimulation was observed with 1 microgram FSH/ml which resulted in a 2.5-fold increase over control values. Dibutyryl cyclic AMP (dbcAMP) also caused a dose-related increase in lactate production by these cells. Luteinizing hormone (LH), insulin, testosterone or 17 beta-estradiol had no similar effect on lactate production by these cells. Peritoneal macrophages were not responsive to FSH or dbcAMP. These studies demonstrate that a highly enriched population of testicular macrophages can be maintained in culture and express several immunological characteristics traditionally ascribed to macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
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