ZFIN ID: ZDB-PUB-041012-5
Localization and expression of aromatase mRNA in adult zebrafish
Goto-Kazeto, R., Kight, K.E., Zohar, Y., Place, A.R., and Trant, J.M.
Date: 2004
Source: General and comparative endocrinology   139(1): 72-84 (Journal)
Registered Authors: Zohar, Yonathan
Keywords: Cytochrome P450 aromatase; CYP19A1; CYP19A2; In situ hybridization; Brain; Gonad; Neural
MeSH Terms:
  • Animals
  • Aromatase/genetics
  • Aromatase/metabolism*
  • Brain/enzymology
  • Female
  • In Situ Hybridization
  • Isoenzymes/genetics
  • Isoenzymes/metabolism
  • Male
  • Ovarian Follicle/enzymology
  • Ovarian Follicle/physiology
  • Pituitary Gland/enzymology
  • RNA, Messenger/metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sex Factors
  • Tissue Distribution
  • Zebrafish/metabolism*
  • Zebrafish/physiology
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 15474538 Full text @ Gen. Comp. Endocrinol.
Estradiol plays a key role in the control of many behavioral and physiological aspects of reproduction therefore the expression of cytochrome P450 aromatase (CYP19), the enzyme responsible for the conversion of androgens to estrogens, is of vital interest. The zebrafish, and many other teleosts, have two aromatase genes (CYP19A1 and CYP19A2) that are expressed predominantly in the ovary and brain, respectively, however, the physiological impact of extra-gonadal aromatase has been poorly described. In this study, in situ hybridizations of whole-mount and paraffin sections of adult zebrafish brains, pituitaries, and ovarian follicles showed that CYP19A2 was strongly expressed in the olfactory bulb (OB), ventral telencephalon (TEL), preoptic area (POA), and ventral/caudal hypothalamic zone (HT) of the brain, and in the anterior and posterior lobes of the pituitary. The regional distribution of the CYP19A2 mRNA did not vary with sex however transcript abundance varied within (male "high expressers" had much higher expression in the OB, TEL, and HT than in "low expressers") and between sexes (higher in OB, TEL, and HT of males than in females). In situ hybridizations of CYP19A1 failed to develop a signal in the brain or pituitary but were detectable by RT-PCR. CYP19A1 was highly expressed in Stage III B follicles (>500nm) with significantly lower levels in the Stage IV follicles (>680nm), Stage III A follicles (>350nm), and Stage I and II follicles (350μm) which were embedded in connective tissues. The differential expression of the aromatase genes, particularly CYP19A2 in the brain, suggests that the two aromatase genes play different roles in the reproductive behavior and/or physiology of bony fish.