Thyrotropes (which produce TSH) present.
Kaplan SL, Grumbach MM, Aubert ML. 1976. The ontogenesis of pituitary hormones and hypothalamic factors in the human fetus: maturation of central nervous system regulation of anterior pituitary function. Recent Prog Horm Res 32:161-243.
Gonadotropes for FSH present.
Sadler TW. 2000. Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect 108 (suppl 3):555-561.
Lateral tuberal nucleus becomes visible; fornix continues to mature; intermediate nucleus is well defined; mammillary complex is well-differentiated by week 15.
Duration: 2 weeks
Koutcherov Y, Mai JK, Paxinos G. 2003 Dec. Hypothalamus of the human fetus. J Chem Neuroanat 26(4):253-70.
Craniofacial: Ossification of the skull begins, following a defined sequence.
Moore KL, Persaud TVN. 1998. The Developing Human: Clinically Oriented Embryology. 6th ed. Philadelphia: WB Saunders Co.
Primitive islet structures express all four pancreatic hormones (insulin, glucagon, somatostatin, and pancreatic polypeptide).
Piper K, Brickwood S, Turnpenny LW, Cameron IT, Ball SG, Wilson DI, Hanley NA. 2004 Apr. Beta cell differentiation during early human pancreas development. J Endocrinol 181(1):11-23.
Fetal zone cells show immunostaining for human growth hormone receptors.
Duration: 1 week
Simard M, Manthos H, Giaid A, Lefebvre Y, Goodyer CG. 1996 Aug. Ontogeny of growth hormone receptors in human tissues: an immunohistochemical study. J Clin Endocrinol Metab 81(8):3097-102.