Biology of Reproduction Summers

Endocrinology Homeostasis/Feedback Adult Female Steroid Production Ovulation

Adult Male Gonadal Axis Regulation Sexual Differentiation Sexual Behavior Puberty

Reproductive Cycling Estrous Cycles Menstrual Cycle Menopause Fertilization

Fertilization Systems Gamete Interaction Pregnancy Labor and Parturition Lactation

Sexual Response & Behavior Pheromones STDs text: Human Reproductive Biology2nd Edition- RE Jones & KH Lopez,: pp 24-28 Acronyms/Abbreviations    end

VIII. Steroid Production 	

	A. one of the 1o functions of follicle cells


	B. Estrogens: any compound that causes the uterus to grow


		1. 3 natural endogenous estrogens


			a. E2 = estradiol-17b


			b. E1 = estrone


			c. E3 = estriol

		
		2. environmental estrogens may come from plants or
		    degradation of industrial biochemicals like pesticides


	C. Progestogens: any compound that allows embryo
				  to implant/grow in the uterus


		1. P (progesterone)  (peripheral)


		2. in the brain


			a. THP = allopregnanolone = 3a-OH-DHP


			b. Preg-S = pregnenolone sulfate


	D. Androgens: any compound which will stimulate
				 growth of the seminal vesicles


		1. potent: most common in men


			a. T = testosterone


			b.  DHT = dihydrotestosterone


		2. weak androgens: measured most commonly in women


			a. DHEA = dehydroepiandosterone


			b. androstenedione


	E. steroidogenesis


				cholesterol

					¯

				pregnenolone

					¯

				17-hydroxypregnenolone

					¯

				     DHEA ® androstenedione
					 
			   


		1. D5 pathway = ® = main follicular source of steroids from the ovay



			a. Tertiary follicles


		Theca			  	                Granulosa


			*LH
 cholesterol ®  ® pregnenolone
		                   D5  ¯
                                           ¯ transported by diffusion
	                  androstenedione- - - - - - - - - ®

									      ¯

									      T

									      ¯

									      ¯ *FSH

	*required							E2




	F. Corpus Luteum (yellow body)


		1. formed after ovulation


		2. Luteinization


			a. product of LH surge (name of LH)


				i. begins just before ovulation


			b. theca thickens


			c. granulosa divides (mitosis)


				i. very fast


			d. these cells now = luteal cells




			e. steroidogenic - D4 pathway = ®


				cholesterol

				      ¯
							       D4
				pregnenolone ® ® ® ® ® ® Progesterone

				       ¯					      ¯

				17-OH-preg  	   		          17-OH-P

				      ¯					              ¯

				DHEA ® ® ® ® ® ® ® ® androstenedione



		Theca			    	            Luteal cells (granulosa)

		    D5					    cholesterol ® pregnenolone
										        ¯
									                ¯ D4
									                P  ®  blood (most)
								                       ¯ 	     
								                       ¯ (small amt)
								                 17-OH-P

										          ¯

										         andro

										           ¯

										           E1 ® E2


			f. 3o follicle = 1/4 P : 3/4 E2

				i. E2 stimulates LH surge via + feedback


				ii. \ luteinization


			g. Corpus luteum = 2/3 P : 1/3 E2