Ontogenetic profile of the expression of thyroid hormone receptors in rat and human corpora cavernosa of the penis.
BACKGROUND
In the last few years, various studies have underlined a correlation between thyroid function and male sexual function, hypothesizing a direct action of thyroid hormones on the penis.


OBJECTIVE
To study the spatiotemporal distribution of mRNA for the thyroid hormone nuclear receptors (TR) alpha1, alpha2 and beta in the penis and smooth muscle cells (SMCs) of the corpora cavernosa of rats and humans during development.


METHODS
We used several molecular biology techniques to study the TR expression in whole tissues or primary cultures from human and rodent penile tissues of different ages.


METHODS
We measured our data by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) amplification, Northern blot and immunohistochemistry.


RESULTS
We found that TRalpha1 and TRalpha2 are both expressed in the penis and in SMCs during ontogenesis without development-dependent changes. However, in the rodent model, TRbeta shows an increase from 3 to 6 days post natum (dpn) to 20 dpn, remaining high in adulthood. The same expression profile was observed in humans. While the expression of TRbeta is strictly regulated by development, TRalpha1 is the principal isoform present in corpora cavernosa, suggesting its importance in SMC function. These results have been confirmed by immunohistochemistry localization in SMCs and endothelial cells of the corpora cavernosa.


CONCLUSIONS
The presence of TRs in the penis provides the biological basis for the direct action of thyroid hormones on this organ. Given this evidence, physicians would be advised to investigate sexual function in men with thyroid disorders.
Course of Endocrinology and Medical Sexology, Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy.
Eleonora
E
Carosa
Stefania
S
Di Sante
Simona
S
Rossi
Alessandra
A
Castri
Fabio
F
D'Adamo
Giovanni Luca
GL
Gravina
Piero
P
Ronchi
Zdenek
Z
Kostrouch
Susanna
S
Dolci
Andrea
A
Lenzi
Emmanuele A
EA
Jannini
D000368:Aged; D000375:Aging / Q000502:physiology*; D000483:Alleles; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism*; D010413:Penis / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012741:Sexual Maturation / Q000235:genetics; D013045:Species Specificity; D037021:Thyroid Hormone Receptors alpha / Q000235:genetics*; D037042:Thyroid Hormone Receptors beta / Q000235:genetics*
D012333:RNA, Messenger; D037021:Thyroid Hormone Receptors alpha; D037042:Thyroid Hormone Receptors beta